1. Field of the Invention
This invention pertains to excavating, earth working and material handling equipment generally, and specifically to loader scoop or bucket attachments that are designed for efficient rock picking or for material loading, and transport of either.
2. Description of the Related Art
Many industries use front-end loaders and tractors, which are highly versatile machines. Generally configured with a front end bucket, these machines are capable of transporting many thousands of pounds of materials. Most loaders are capable of maneuvering about in relatively small spaces, further adding to their versatility. The bucket is useful for scooping from large piles or smooth surfaces, and so may be used not only for moving materials about but also for cleaning up surfaces.
However, a standard bucket has a lateral leading edge which is difficult to use for irregular materials such as logs or pallets. Further limiting a front-end loader is the relative difficulty of using the bucket for digging into dense or packed materials such as the earth, or scraping the irregular ground. Recognizing these limitations of a scoop or bucket, and yet also understanding the vast potential for these compact and powerful machines, previous inventors have designed alternative attachments for front-end loaders. Among the inventions are those illustrated in U.S. Pat. No. 3,557,877 to Hoffman, U.S. Pat. No. 3,643,821 to Viel, and U.S. Pat. No. 4,303,507 to Smith, the teachings of each incorporated herein by reference.
Hoffman discloses an attachment, referred to as a picker head, for a tractor or the like. The picker head, which replaces the standard bucket, consists of a plurality of longitudinal, parallel teeth. The teeth are spaced from each other, which improves penetration of the earth and also ensures that any dirt which is gathered with rock will drop back to the earth and not be retained in the picker head. The picker head may also be used to scrape along the irregular earth surface to sift rocks from any loose top soil.
Viel discloses an attachment similar to Hoffman, and, like Hoffman, discloses the rock picker as a replacement for the bucket. Like Hoffman, the Viel design discloses a plurality of longitudinal, parallel teeth for picking rocks. In the Viel design, the tractor hydraulics are used to move and orient the rock picker attachment. Neither Hoffman or Viel provide a way to pick rocks or other debris, load, and then continue to pick. Rather, in the Hoffman and Viel designs, the picker attachment is used as a replacement for the loader bucket. Where a large number of rocks or several very large rocks or other debris need loaded, the lack of a loader bucket is a distinct disadvantage.
Several additional disadvantages exist in the Viel and Hoffman designs. The use of the picker head as the debris carrying structure limits the operator to only one type of debris in a load. For example, brush or fallen logs and rocks may both need to be removed from a location. The brush will normally be unloaded in one place, such as for burning, composting, etc., while rocks will normally be deposited elsewhere.
Furthermore, the picker head is designed for picking, not for holding material. The picker head is flat, with no side walls. A loader bucket has deep side walls designed for retaining material in the bucket. When hauling rock or other debris, very little may be carried directly on the picker head without dropping therefrom. Being able to transfer the material to some other container such as the loader bucket for transport would be a distinct advantage.
Another disadvantage of the Hoffman and Viel designs occurs during unloading. Directly controlling the attachment with hydraulics or cables limits how fast the attachment may be moved.
Some materials are more difficult to remove, and so may not be adequately unloaded by the Hoffman and Viel designs.
Smith discloses a scraper sifter which hangs from a bucket by chains. The chains provide a lost-motion connection, allowing the bucket to float over surface irregularities in the ground. However, due also to the chain connection, the Smith invention is unable to be used for digging.
Other attachments and free-standing rock pickers are illustrated in U.S. Pat. Nos. 2,491,079, 2,617,210, 3,082,828, 3,100,540, 3,596,764, 4,411,585, 4,729,180, and D361,772, the teachings of each incorporated herein by reference. Nevertheless, none of these prior-art rock pickers have met each of the needs of agriculture.
In my U.S. Pat. No. 5,664,348, also incorporated herein by reference, I disclose a rock picker which addresses many of the needs which were previously wanting. In that patent, I disclose a toothed rock picker which may be readily attached to an existing front-end loader. The rock picker is actuated without the need for special hydraulics, and includes a solid fence for retaining debris or other matter in the loader. By virtue of the novel construction, a wide range of sizes and types of materials may be handled successfully. Nevertheless, certain disadvantages of that design have been noted. In particular, the use of a solid fence restricts visibility during picking and loading operations. Furthermore, for some applications, is desirable to be able to retrofit hydraulic controls. Finally, in some applications it may be preferable for the material loader to be operated from a fixed position, rather than allow the material loader to rotate.